Research: The interplay between migration and disease
When can the risk and cost associated with parasite infection favor hosts to migrate seasonally?
Many factors are known to drive the seasonal round-trip migration of animals, yet parasites and pathogens are rarely considered among these. We have shown that migration can lower infection prevalence in a population by three different mechanisms (Johns & Shaw 2016). We find that, across biological systems, migrants should generally have lower infection prevalence and infection intensity (compared to residents) but should simultaneously have higher parasite diversity (Shaw et al. 2018, Balstad et al. 2021). Furthermore, migration can be favored as a strategy to reduce infection costs even when migration increases the diversity of parasites infecting an individual (Shaw et al. 2018). We show that migration can be favored as a strategy to reduce infection and is most easily favored when the cost of migration is paid in terms of reduced fecundity, while the cost of infection is paid in terms of reduced survival (Shaw et al. 2019). We proposed that migration can also evolve if it allows parasitized individuals to recover from infection, e.g., by crossing a strong salinity gradient ("migratory recovery"; Shaw & Binning 2016). We have also shown that migratory recovery should be a more widespread benefit to migrating than just escaping parasites ("migratory escape") (Naven Narayanan et al 2020, Shaw & Binning 2020). Finally, we provide ideas for empirical future research on migration and parasites, based on some of our theoretical findings (Binning et al 2022).
This work was conducted primarily as part of an NSF DEB grant (2017-2023) in collaboration with Sandra Binning, Meggan Craft and Marlene Zuk.
Many factors are known to drive the seasonal round-trip migration of animals, yet parasites and pathogens are rarely considered among these. We have shown that migration can lower infection prevalence in a population by three different mechanisms (Johns & Shaw 2016). We find that, across biological systems, migrants should generally have lower infection prevalence and infection intensity (compared to residents) but should simultaneously have higher parasite diversity (Shaw et al. 2018, Balstad et al. 2021). Furthermore, migration can be favored as a strategy to reduce infection costs even when migration increases the diversity of parasites infecting an individual (Shaw et al. 2018). We show that migration can be favored as a strategy to reduce infection and is most easily favored when the cost of migration is paid in terms of reduced fecundity, while the cost of infection is paid in terms of reduced survival (Shaw et al. 2019). We proposed that migration can also evolve if it allows parasitized individuals to recover from infection, e.g., by crossing a strong salinity gradient ("migratory recovery"; Shaw & Binning 2016). We have also shown that migratory recovery should be a more widespread benefit to migrating than just escaping parasites ("migratory escape") (Naven Narayanan et al 2020, Shaw & Binning 2020). Finally, we provide ideas for empirical future research on migration and parasites, based on some of our theoretical findings (Binning et al 2022).
This work was conducted primarily as part of an NSF DEB grant (2017-2023) in collaboration with Sandra Binning, Meggan Craft and Marlene Zuk.
Example of the dynamics of infection in a migratory species (adapted from Fig. 1 in Johns & Shaw 2016).
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Relevant papers
Hall RJ, Altizer S, Peacock SJ, Shaw AK. Animal migration and infection dynamics: recent advances and future frontiers. In: Ezenwa VO, Altizer SA, Hall RJ, editors. Animal Behavior and Parasitism. Oxford University Press, 2022. DOI: 10.1093/oso/9780192895561.003.0007
Binning SA, Craft ME, Zuk M, Shaw AK (2022) "How to study parasites and host migration: A roadmap for empiricists." Biological Reviews 97(3): 1161-1178.
Kim D, Shaw AK (2021) "Migration and tolerance shape host behavior and response to parasites infection" Journal of Animal Ecology 90(10): 2315-2324.
Balstad LJ, Binning SA, Craft ME, Zuk M, Shaw AK (2021) "Parasite intensity and the evolution of migratory behavior." Ecology 102(2): e03229.
Shaw AK, White LA, Michalska-Smith M, Borer ET, Craft ME, Seabloom EW, Snell-Rood E, Travisano M (2021) "Lessons from movement ecology for the return to work: modeling contacts and the spread of COVID-19" PLoS ONE 16(1): 20190590.
Naven Narayanan, Binning SA, Shaw AK (2020) "Infection state can affect host migratory decisions." Oikos 129:1493-1503.
Shaw AK, Binning SA (2020) "Recovery from infection is more likely to favor the evolution of migration than social escape from infection." Journal of Animal Ecology 89(6): 1448-1457.
Shaw AK, Craft ME, Zuk M, Binning SA (2019) "Host migration strategy is shaped by forms of parasite transmission and infection cost." Journal of Animal Ecology 88(10) 1601-1602.
Shaw AK, Sherman J, Barker FK, Zuk M (2018) "Metrics matter: the effect of parasite richness, intensity and prevalence on the evolution of host migration." Proceedings of the Royal Society B 285(1891): 20182147.
Binning SA, Shaw AK, Roche DG (2017) "Parasites and host performance: incorporating infection into our understanding of animal movement." Integrative and Comparative Biology 57(2): 267-280.
Shaw AK, Binning S (2016) "Migratory recovery from infection as a selective pressure for the evolution of migration." American Naturalist 187(4): 491-501.
Johns S, Shaw AK (2016) "Theoretical insight into three disease-related benefits of migration." Population Ecology 58(1): 213-221.
Binning SA, Craft ME, Zuk M, Shaw AK (2022) "How to study parasites and host migration: A roadmap for empiricists." Biological Reviews 97(3): 1161-1178.
Kim D, Shaw AK (2021) "Migration and tolerance shape host behavior and response to parasites infection" Journal of Animal Ecology 90(10): 2315-2324.
Balstad LJ, Binning SA, Craft ME, Zuk M, Shaw AK (2021) "Parasite intensity and the evolution of migratory behavior." Ecology 102(2): e03229.
Shaw AK, White LA, Michalska-Smith M, Borer ET, Craft ME, Seabloom EW, Snell-Rood E, Travisano M (2021) "Lessons from movement ecology for the return to work: modeling contacts and the spread of COVID-19" PLoS ONE 16(1): 20190590.
Naven Narayanan, Binning SA, Shaw AK (2020) "Infection state can affect host migratory decisions." Oikos 129:1493-1503.
Shaw AK, Binning SA (2020) "Recovery from infection is more likely to favor the evolution of migration than social escape from infection." Journal of Animal Ecology 89(6): 1448-1457.
Shaw AK, Craft ME, Zuk M, Binning SA (2019) "Host migration strategy is shaped by forms of parasite transmission and infection cost." Journal of Animal Ecology 88(10) 1601-1602.
Shaw AK, Sherman J, Barker FK, Zuk M (2018) "Metrics matter: the effect of parasite richness, intensity and prevalence on the evolution of host migration." Proceedings of the Royal Society B 285(1891): 20182147.
Binning SA, Shaw AK, Roche DG (2017) "Parasites and host performance: incorporating infection into our understanding of animal movement." Integrative and Comparative Biology 57(2): 267-280.
Shaw AK, Binning S (2016) "Migratory recovery from infection as a selective pressure for the evolution of migration." American Naturalist 187(4): 491-501.
Johns S, Shaw AK (2016) "Theoretical insight into three disease-related benefits of migration." Population Ecology 58(1): 213-221.
